What is a Green Roof and why are they rising in popularity?
Over the last decade, you may have come across what is known as a green roof. Unlike a common and garden industrial roof, it is one that is topped with vegetation. There is also a growing medium, which enables the roof to keep its shape. There may be additional layers designed to keep the roof waterproof, such as a root barrier and an irrigation system.
There is more than one variety of green roof. One example, known as the extensive green roof, goes even further than the standard variety. Instead of comprising of grass as its sole material, it also includes sedums, herbs, and flowering herbaceous plants. Irrigation channels are omitted and maintenance is low.
A sedum-based green roof comprises solely of sedums. Sedum matting has shallow roots, which makes the grass variety suitable for environmentally friendly roofs.
Green roofs or living roofs: what’s the difference?
None whatsoever. A living roof is an alternative term for a green roof.
Intensive, Semi Intensive or Extensive: what is the difference?
An intensive green roof allows for thick cover whereas an extensive green roof offers thinner cover. With the former, this allows for the planting of grasses and wild flowers with deeper roots. The latter is suitable for grasses with shallow roots, like sedum matting.
What are the main benefits?
They can expand the lifespan of a conventional roof by 200%. In other words, it is claimed that a roof with a 30-year guarantee could last for 90 years. The grass shields the membrane from damage by ultraviolet rays and physical damage.
Energy use is also reduced. The grass acts as an insulated layer for the roof underneath.
Why are they rising in popularity?
As a lot of energy is lost from roof space, energy use is cut dramatically with a living roof. The grass and wild flowers improve the roof’s resilience and insulation properties. It also attracts wildlife and cuts CO2 emissions.
KC Smith Roofing, 01 December 2016.
A living roof on L’Historial de la Vendée by SiGarb – Own work, Public Domain, Link